We
are seeing a lot of profound changes going on at NASA these days. The
one that I want to talk about this evening is how NASA is setting its
course for the future. With all the reinventing, downsizing, and streamlining,
where is it that we are going? Do we have a compelling vision for our
next era in space?

In
the past, the approach to the future was driven by competition with the
Soviet Union. NASA's feats were ones of technical derring-do, designed
to show superior competence in engineering. All this changed with the
end of the Cold War. Today we are in the process of formulating a vision
for the future which is driven by the search for answers to fundamental
questions about planet Earth, its neighborhood the solar system, and the
Universe. And by fundamental questions about ourselves, the origin of
life, and the possibility of finding other planets that are alive. We
still need to demonstrate excellence in engineering, but we need to do
this to accomplish our scientific goals, not just to demonstrate technical
superiority. We realize that we can do much more in partnership: at home,
by uniting federal government with industry and academia, and abroad,
by forming international alliances. Instead of talking about competing
with Russia, we are looking for more ways to collaborate with her and
with many other countries.

How
are we building a road map for the future? One of our ways is quite extraordinary,
and it is this way that I want to share with you. NASA Headquarters sits
adjacent to a huge highway in SW Washington D.C. Its a block-long unmemorable
building containing only offices, almost all of them modular and gray.
It's not a work of art. The only singular room is an auditorium, to which
the press is invited for press conferences and NASA employees are occasionally
invited to receive medals. It is here that once a month the Administrator
of NASA, Mr. Daniel Goldin, has been inviting leading scientists, theologians,
historians, and other thinkers to discuss what would be a significant
agenda for America's next era in space, an agenda that is both profound
in its search for truth, compelling because of its far reach, and inspiring
to the public. We are only a third of the way through this year long exploratory
process, but already we are starting to see a road map taking shape. It
is unusual, perhaps unprecedented, for a federal agency to engage in anything
like an intellectual dialog with itself and its customers -- and to expect
that that dialog will need to a driving vision for the next century.

What
are we learning? First, we find that our view of the universe has changed
greatly in the last 60 years since Edwin Hubble discovered the recession
of the galaxies, that they were all moving away from each other, that
the universe was expanding and was 10 to 20 billion years old. His discovery
was an incredible change in our world view, a change as profound as the
Copernican revolution.

We
have a fancy name for a world view, we call it cosmology because it deals
with our "myth" for the origin and workings of the cosmos at
large. At the time of Edwin Hubble, a half century ago, we believed that
the cosmos was homogeneous, uniform, isotropic. But today our world view
is undergoing another profound change. As a result of applying new large
telescopes to the study of the universe -- telescopes on the ground and
in space -- and techniques like adaptive optics -- we have recently discovered
that the universe is clumpy and huge sectors of it are moving in specific
directions because of gravity [Figure 1: The non-uniform distribution
of galaxies, from the work of Drs. Geller and Huchra]. With new, much
more precise measurements all of our cherished concepts and numbers are
challenged: we have less confidence, not more, about the true size, age,
and density of the universe, whether it will continually expand, or is
slowing down and will eventually close in on itself.

We
don't understand why the universe is clumpy -- why there are galaxies
and clusters of galaxies -- why the radiation left over from the Big Bang
that was its origin is so smoothly distributed [Figure 2: smooth 3 degrees
Kelvin background (96 kb) as observed by NASA's Cosmic Background Explorer
Satellite, or COBE]. We used to think that the galaxies were far apart
from each other; now we appreciate that, relative to the scale of the
universe they are so close that they bang into each other and produce
weird shapes and patterns of radiation [Figure 3: colliding galaxies (64
kb) ]. We recently discovered that the universe appears to be younger
than the stars that fill it -- a notion that hardly makes sense until
you realize that, with all our new technologies, our measurements still
lack precision [Figure 4: Hubble Space Telescope observations of Cepheid
variables (64 kb) in another galaxy give us clues to age of the universe].

There
are four numbers we would like to know: the amount of matter in the universe;
the energy density of the vacuum that is space; the Hubble constant; and
the transverse motions of galaxies. These four measurements are fundamental
to our understanding of the birth and evolution of the cosmos. Yet we
are far from being able to measure any of these fundamental parameters
well. We lack aperture and we lack baseline, and without this, without
extremely large telescopes in a stable configuration in space, above the
Earth's distorting atmosphere, we cannot see beyond the local disturbances
in the flow of galaxies, and we cannot measure precisely the tiny motions
of stars in far-off galaxies. The Hubble Space Telescope is a great telescope,
but a limited one. To do better, at an affordable price, we will have
to find ways of building much larger, lighter telescopes, a constellation
of them spread over a great area of the sky (or the surface of the Moon)
and carefully networked together to operate as one giant dish in space.

Second,
we are learning about ourselves, what it means to be "alive."
If we are going to pioneer the solar system and beyond, it would be good
to have a definition of what constitutes cellular life, and how we would
recognize signs of life elsewhere. Surely the knowledge that there is
life elsewhere, either now or in the past, would revolutionize our view
of ourselves in the Universe. Trying to answer the question of whether
or not there is life elsewhere used to be idle conjecture, but now we
have the wherewithal to find out. We learned from our seminar speakers
that one way to detect life is to look for organic molecules in samples
and to look for a degree of complexity that could not arise by accident.
We should look for a large number of equivalent molecules (on the basis
that this would not be an accident) or polymers of a defined signature
coming up frequently -- in other words, look for nonrandom phenomena as
a sign of life.

Where
should we look for signs of life? Our experts favored taking samples from
Mars and looking for fossil evidence of organic chemicals. Titan, the
moon of Saturn, is another possibility, as is a comet, which is made of
the material that was early Earth [Figure 5: NASA's and ESA's Cassini
mission will probe Titan (48 kb) for signs of life early in the next century].
Some scientists make the case that life is a planetary phenomenon and
grows exponentially under the right conditions. All our experts agreed
that if you have the right environment, life will appear very quickly,
and there is ample evidence on our own planet to show that this is true=2E
There are, after all, 30 million species on our planet, some with origins
3.5 billion years old. Interestingly, RNA sequencing shows that there
is only one form of life on Earth; we are all made of the same stuff.
Our common ancestor, we learn from the experts, was a thermophytic sulfur
bacterium!

The
particular abundance of elements on the Earth is its signature of life,
cell biologists and chemists argue. Earth differs from Mars and Venus
in that it has more oxygen, nitrogen, and water, and less carbon dioxide
-- and Earth is at room temperature. They point out that it is nonhuman
life that has changed our planet, that organisms regulate the planet and
have made it what it is for 3000 million years; these organisms removed
carbon dioxide and produced the large amount of oxygen we have. Life will
grow and grow and expand, given only water and food to reproduce. These
organisms have made the air and soil suitable for human life. On any other
planet that has signs of life we should expect again to find life as an
integrated, whole planet system. This requires carbon, nitrogen, sulfur,
and water. The search for life on other planets is equivalent to searching
for liquid water. Our task should be to measure the surface temperature
of planetary bodies at microwave wavelengths to see if there is liquid
water. Mars could be habitable but isn't [Figure 6: Hubble Telescope image
of Mars (48 kb) ]. It may have had liquid water in the past, but it's
gone now. Mars is much smaller than the Earth. There is no active plate
tectonics and it can't maintain the dynamic interactions that Earth can.

Do
we have to limit our search for signs of life to our own solar system?
Do we have evidence for other solar systems? Our first real evidence that
these probably exist came in 1983 with observations by NASA's Infrared
Astronomy Satellite, IRAS, which discovered infrared-emitting "fuzz"
around the images of nearby stars. More recently the Hubble Space Telescope
has imaged clearly a stellar nursery called the Orion Nebula and discovered
that about 50% of the stars have disks of gas around them that could be
solar systems in the making [Figure 7: Hubble Telescope images of protoplanetary
nebulae]. With present technology, especially speckle interferometry,
we could probably image Jupiters around other solar systems from the ground.
With space technology, we could image Earths orbiting other suns.

We
have the beginning of a road map. We have signs of life to search for,
and we have identified places that could enable this exploration: on the
Moon a wide, stable interferometer could be placed to image distant Earths
and to use as a jumping off point for Mars, where robots or humans will
search for evidence of fossil life. An interferometer with large aperture
dishes could also be used to measure with much greater precision the vital
statistics of the cosmos: how big is it? how old is it? what was its beginning?
and what is its end? These two explorations have a connection; it is ourselves:
why are we here? what is our purpose? Historians tell us that these are
questions that ancient civilizations not only asked themselves, but built
elaborate cosmologies to answer. Interestingly, the difference, for example,
between their cosmologies and ours is that theirs were founded on images
that every man, woman, and child could easily connect with (take the Mayan
metaphor of the Milky Way as a canoe), whereas ours are abstracted into
numbers like Omega, lambda, and H-naught.

Is
this vision realizable? Can we hope, for example, to identify an Earth
orbiting another star? Or quantify the numbers that underpin our cosmology?
Yes, it is! Right now scientists and engineers are forming teams to study
the new technologies that we will need: nonlinear optics, hyperspectral
sensors, adaptive optics, laser ranging, interferometers, methods for
precise station keeping, ... It will take an integrated, multidisciplinary
effort, but that is something that NASA is good at. Only NASA looks at
the whole planet, not the separate disciplines of biology, geology, physics,
etc., and it is this unified approach that we'll need to accomplish our
ambitious goal. What is the challenge? Look at this slide.....[Figure
8: Dr. Robert Brown's computer-generated image of an Earth-like planet
viewed at 10 parsec with different resolutions]... the technical challenge
is great, but we see its possibility and you see its power.

Our
dialog on NASA's next era in space is just beginning. Having looked at
some issues in biology, planetary science, and astrophysics, we are now
planning to take a closer look at the science of the Earth. We want to
understand much better the impact natural and human factors have had on
our planet, that's the motivation for our Mission to Planet Earth. It
turns out that we know more about the sun, and some of the nearby planets
-- their atmospheres and chemistry and landscapes -- than we do about
our own Planet Earth. Ironically, it was our voyages outward, to the Moon
and the planets, that made us look at our own planet in an entirely new
way. We had not considered remotely sensing ourselves! Our view of Earth
from the Shuttle shook us up [Figures 9 - 13: Sahara dust storm (from
Shuttle); Brazil-Bolivia border deforestation (from Landsat); African
biomass fires (from Shuttle); Madagascar soil erosion (from Shuttle),
Mozambique deforestation and silt build-up in rivers (from Shuttle)].

Our
vision is that we learn to be excellent caretakers of our global "backyard"
for future generations. To do this we will need to understand how all
the parts are related to the whole. And this will require a vast information
network. This slide [Figure 14: cartoon of national information network]
reveals a world with a digital pulse, a world aware of itself.

And,
finally, in our dialog through the remainder of this year, we will explore
our own role in this adventure. What will human beings do in space? Perhaps
we'll need human beings because we've always been adventurers, because
we can make decisions machines can't and because we can do challenging
space experiments that require the skill of a surgeon. Perhaps we need
to involve machines that have consciousness, and that can live longer
than a human life span. Our dialog at NASA will take us into the science
of consciousness and the new technologies life and medical sciences are
offering that may enable some progeny of ourselves, a mating of human
and machine, to explore beyond our solar system.

To
get ready to explore and utilize space, we use the Space Shuttle as a
laboratory and, soon, we will enjoy the much longer duration laboratory
capability of the Space Station. On planet Earth we are 5 billion astronauts
on a space ship hurtling through space at 500,000 miles per hour. Our
spaceship experiences precisely one "g." But we can alter gravity,
one of nature's four forces, by going into space. This profound capability
allows us to explore the natural world that we take for granted, including
our own bodies and common processes, in a much different way, allowing
us insight into physics that is masqued on Earth by the effects of gravity.
On the Shuttle we investigate in a much reduced gravity the behavior of
living cells, fluids, proteins and processes like combustion and phase
transitions. We've been encouraged by our successes and the interest of
industry in this research. We envision that space is slowly transforming
into the province of not just a few, but of many.

We
hope that the end of our search for an integrating agenda in space will
bring us a new vision of what is possible, and new ideas about the technologies
we will need to achieve this vision. We want it to be a distinctly human
vision, one that satisfies a need that is deep in the psyche of most of
us. We want to leave the legacy that a young astronomer, Dr. Dan Lester
at UT Austin, talked about when he recently testified before Congress:

"The
heritage that we leave for future generations is not just knowledge of
the scale of the Universe, or evidence for black holes in the hearts of
galaxies, but the spirit of exploration of the world around us. For it
is this spirit of exploration, and the curiosity that drives it, that
is one of our most profound national needs. A nation that stops exploring
is a nation that cannot produce the scientists and technologist that we
so desperately need to be competitive in the global economy, and to improve
the human condition. Federally funded scientific research is a contract
with the US taxpayer not only to create new products, but to satisfy the
national curiosity about the world in which we live. It is a fundamental
element in the federal investment portfolio that insures our leadership
in the world."

I'd
like to close by showing you this portrait of a cluster of galaxies [Figure
15: Hale Observatories image of 5 galaxies]. This is a multitude of Milky
Ways, each the host 10 billion stars. Ten billion galaxies in our Universe
times 10 billion stars in each -- and yet we know of only one solar system
and only one life-bearing planet [Figure 16: Planet Earth (as viewed from
Apollo XVII) (395 kb)]. To view ourselves, our home, from a remote suburb
in space .... and to view the evolution of the Universe back to nearly
its origins.... These are remarkable capabilities that empower us to continually
renew our view of our own purpose on this planet and our final connection
with the stars.

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